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304 stainless steel is a general-purpose austenitic stainless steel selected for its balanced corrosion resistance, formability, weldability and manufacturing versatility.
Stainless Steel 304
NAITE TECH
- Stainless Steel
August 2026
CNC machining, sheet metal processing, Forging, Forming, Laser Cutting, Welding, Bending, Brazing, Deep Drawing, Drilling, Fabrication, Grinding, Heat Treatment, Sheet Forming, Stamping
- Corrosion Resistant, - High Temperature, - Chemical Resistant
Sheet Metal Enclosures / Equipment Housings / Brackets & Mounting Plates / Food Processing Equipment / Tanks & Containers / Fluid Components / Industrial Fabrications / Fasteners / General Mechanical Components
$$ - Moderate
Technical Data
304 stainless steel is a general-purpose austenitic stainless steel used where corrosion resistance, formability and weldability are all important. It is commonly specified for sheet metal fabrications, equipment housings, tanks, food-processing equipment, brackets, fluid-handling components and other industrial applications.
This page provides engineering reference data for 304 stainless steel, including composition, mechanical and physical properties, corrosion behavior, manufacturing characteristics, material conditions, surface finishes, common specifications and guidance on when to select another stainless steel grade.
304 Stainless Steel at a Glance
Property | 304 Stainless Steel |
|---|---|
Stainless Steel Family | Austenitic |
UNS Designation | S30400 |
EN Material Number | 1.4301 |
Primary Strength | General-purpose corrosion resistance and fabrication performance |
General Corrosion Resistance | Good |
Machinability | Moderate |
Weldability | Excellent |
Formability | Excellent |
Hardenable by Heat Treatment | No |
Cold-Work Strengthening | Yes |
Magnetic Behavior | Generally low in the annealed condition; may increase after cold work |
Relative Cost | $$ — Moderate |
Best For | General Industrial / Food Equipment / Sheet Metal / Fabrication |
Typical Applications
Sheet Metal Enclosures / Equipment Housings / Brackets & Mounting Plates / Food Processing Equipment / Tanks & Containers / Fluid Components / Industrial Fabrications / Fasteners / General Mechanical Components
304 is a chromium-nickel austenitic stainless steel designated UNS S30400 and commonly associated with EN 1.4301. It is one of the standard grades used when a component requires good general corrosion resistance together with strong forming and welding performance.
Its austenitic structure gives the material high ductility and allows it to be bent, drawn, stamped and welded without the heat-treatment requirements associated with martensitic stainless steels.
304 cannot be hardened by conventional quenching and tempering. Strength and hardness can, however, increase substantially through cold working.
For applications involving significant chloride exposure, very high mechanical strength or high hardness, another stainless steel grade may be more appropriate.
Good General Corrosion Resistance
Suitable for many atmospheric, freshwater, food-processing and general industrial environments.
Excellent Formability
High ductility supports bending, stamping, deep drawing and other cold-forming operations.
Excellent Weldability
Suitable for a wide range of welded sheet, plate and fabricated assemblies.
Broad Material Availability
Commonly available as sheet, plate, bar, tube, pipe and other standard product forms.
Versatile Manufacturing Behavior
Compatible with machining, cutting, forming, welding, grinding and polishing.
Established Specifications
Available under widely recognized ASTM, EN, UNS and JIS designation systems.
The properties of 304 stainless steel depend on material specification, product form, thickness and condition. The values below are suitable for engineering comparison and preliminary material selection; drawing and purchasing requirements should reference the applicable material standard.
Representative composition limits for UNS S30400 flat-rolled material are shown below.
Element | Composition |
Chromium (Cr) | 17.5–19.5% |
Nickel (Ni) | 8.0–10.5% |
Carbon (C) | ≤ 0.07% |
Manganese (Mn) | ≤ 2.00% |
Silicon (Si) | ≤ 0.75% |
Phosphorus (P) | ≤ 0.045% |
Sulfur (S) | ≤ 0.030% |
Nitrogen (N) | ≤ 0.10% |
Iron (Fe) | Balance |
Chromium is responsible for formation of the passive surface film that gives stainless steel its corrosion resistance. Nickel helps stabilize the austenitic structure and contributes to ductility, toughness and fabrication performance.
Specification Note:
Composition limits can differ slightly between product standards. For example, requirements for bar products under ASTM A276 are not identical to those for flat products. Always verify the specified product standard when purchasing material.
Property | Representative Minimum |
Tensile Strength | 515 MPa |
0.2% Proof / Yield Strength | 205 MPa |
Elongation | 40% |
Hardness | Up to approximately 92 HRB / 201 HB |
Engineering Note:
Mechanical requirements depend on the applicable standard, material form, thickness and condition. Bar, sheet, plate, tube and cold-worked products should be checked against the specification used on the drawing or purchase order.
Property | Typical Value |
Density | Approx. 8.0 g/cm³ |
Elastic Modulus | Approx. 193 GPa |
Thermal Conductivity at Room Temperature | Approx. 16 W/m·K |
Specific Heat Capacity | Approx. 500 J/kg·K |
Electrical Resistivity | Approx. 0.72 µΩ·m |
Thermal Expansion | Approx. 17 µm/m·°C |
Magnetic Behavior | Low in the annealed condition |
Physical-property values are approximate and vary with temperature and material condition.
304 provides reliable general corrosion resistance in many atmospheric, freshwater, food-processing and industrial environments. Its performance is not universal, however. Chloride concentration, temperature, chemical composition, surface condition, deposits, crevices and component geometry can all affect corrosion behavior.
304 performs well in many indoor and moderately exposed outdoor environments. It is widely used for equipment housings, architectural components, industrial fabrications and other applications where ordinary carbon steel would require additional corrosion protection.
Surface finish and exposure conditions remain important, particularly in locations where salts or industrial contaminants can accumulate.
304 is commonly used for tanks, work surfaces, food-processing equipment and freshwater systems because it combines corrosion resistance with good cleanability and fabrication performance.
Material suitability still depends on the process fluid, cleaning chemicals, operating temperature and chloride concentration.
Chlorides increase the risk of localized pitting and crevice corrosion in 304.
For direct saltwater exposure, repeated salt spray, high chloride concentration or demanding coastal service, 316 or 316L is generally a better starting grade because its molybdenum content improves resistance to chloride-induced localized corrosion.
More highly alloyed grades or duplex stainless steels may be required for severe chloride conditions.
304 is resistant to many organic substances and selected inorganic chemicals, but chemical compatibility should never be judged by grade name alone.
Consider:
Chemical type
Concentration
Operating temperature
Exposure time
Chloride content
Aeration
Surface condition
Crevice geometry
For process equipment exposed to aggressive chemicals, material selection should be based on application-specific corrosion data.
Localized corrosion can develop where the passive surface is disrupted, particularly in the presence of chlorides.
Higher-risk locations include:
Gasket interfaces
Lap joints
Threaded connections
Deposits
Fastener interfaces
Poorly drained areas
Shielded surfaces with limited oxygen access
Good drainage, appropriate joint design, clean fabrication practices and suitable surface finishing can reduce risk, but they do not replace correct grade selection.
Austenitic stainless steels such as 304 can be susceptible to chloride stress corrosion cracking when chloride exposure, tensile stress and elevated temperature occur together.
Applications combining these conditions require a more detailed material assessment.
Environment | Suitability | Selection Note |
Indoor General Use | ✅ Good | Common general-purpose choice |
Outdoor Atmospheric Exposure | ✅ Good | Consider local salt and pollution levels |
Freshwater | ✅ Good | Suitable for many general systems |
Food Processing | ✅ Good | Process chemistry and cleaning methods still matter |
Mild Chemical Exposure | ⚠ Evaluate | Check chemical, concentration and temperature |
Coastal Atmosphere | ⚠ Evaluate | Salt deposition can increase localized corrosion |
Direct Saltwater / Marine Service | ⚠ Limited | 316 / 316L is usually a better starting point |
High-Chloride Service | ⚠ Not Preferred | Consider 316L, duplex or higher-alloy grades |
304 is suitable for many atmospheric, food-processing, freshwater and general industrial environments where severe chloride exposure is not expected.
The high ductility of annealed 304 makes it suitable for bending, roll forming, stamping and deep drawing.
Cold deformation progressively work-hardens the material, increasing forming load and springback as the amount of deformation increases.
304 can be welded using common stainless steel welding processes and is widely used in fabricated assemblies.
For heavily welded sections or applications where resistance to sensitization is important, 304L is often specified because of its lower carbon content.
304 can be milled, turned, drilled and tapped, but it does not machine as freely as grades developed specifically for machinability.
Its high work-hardening rate and ductile chip behavior require stable cutting conditions, rigid tooling and avoidance of prolonged rubbing or dwell.
Where machining productivity is the dominant material-selection criterion, 303 may be a better option if its lower corrosion and welding performance are acceptable.
Cold working increases the strength and hardness of 304.
This can be useful when higher mechanical properties are required without changing alloy grade, but it also affects later forming and machining operations.
304 can be supplied and processed with a wide range of mill, brushed, polished and functional surface finishes.
Surface condition is important not only for appearance but also for cleanability, contamination control and corrosion performance.
304 is commonly processed by:
CNC Machining / Laser Cutting / Bending / Deep Drawing / Stamping / Welding / Fabrication / Forging / Drilling / Grinding
304 is not intended to provide the highest performance in every category.
Consider other grades when the main requirement is:
Machining Productivity → 303
Higher Chloride Resistance → 316 / 316L
High Mechanical Strength → 17-4 PH
High Hardness & Wear Resistance → 420 / 440C
Severe Chloride Exposure → Duplex or Higher-Alloy Stainless Steel
304 is compatible with most conventional stainless steel manufacturing processes. The main processing consideration is its tendency to work-harden during cutting and cold deformation.
Manufacturing Process | Compatibility | Material Consideration |
CNC Machining | ✅ Good | Work hardening and ductile chips require controlled cutting |
Sheet Metal Processing | ✅ Excellent | Well suited to fabricated sheet components |
Laser Cutting | ✅ Excellent | Commonly cut in sheet and plate form |
Bending | ✅ Excellent | Allow for springback and increasing forming load |
Deep Drawing | ✅ Excellent | High ductility supports drawn components |
Sheet Forming | ✅ Excellent | Suitable for complex cold-formed geometry |
Stamping | ✅ Excellent | Widely used for formed production components |
Welding | ✅ Excellent | 304L may be preferred for extensive welding |
Fabrication | ✅ Excellent | Suitable for cut, formed and welded assemblies |
Forging | ✅ Good | Can be hot worked using appropriate practice |
Drilling | ✅ Good | Avoid rubbing and work-hardened surfaces |
Grinding | ✅ Excellent | Common for weld cleanup and surface preparation |
During machining, 304 tends to work-harden ahead of the cutting edge. Stable tool engagement is important because rubbing or repeated light contact can harden the surface and accelerate tool wear.
Machining strategy should account for part geometry, material condition, tooling, machine rigidity and heat generation.
Annealed 304 has high ductility and is well suited to bending, stamping and deep drawing.
As deformation increases, work hardening raises strength and forming load. Springback should therefore be considered when establishing bend geometry and forming sequence.
304 has good weldability and is routinely used in welded fabrications.
For extensive welding, thick sections or applications where intergranular corrosion after thermal exposure is a concern, 304L may be specified instead.
304 is commonly supplied in the annealed condition when ductility, formability and corrosion performance are the primary requirements.
Annealed material is the normal starting condition for many sheet, plate and fabrication applications.
Cold rolling, drawing, forming and other deformation processes increase strength and hardness through work hardening.
Increasing cold work generally results in:
Higher yield strength
Higher tensile strength
Higher hardness
Lower ductility
Increased magnetic response in some material
Solution annealing is used to restore a softened austenitic structure after significant cold work or certain thermal histories.
The required treatment depends on material specification, product form and section thickness and should follow the applicable material or process specification.
No.
304 cannot be hardened by conventional quenching and tempering in the way martensitic stainless steels such as 410 or 420 can.
When higher strength or hardness is required, the main options are:
Cold Working → Higher strength and hardness in 304
410 / 420 → Heat-treatable martensitic stainless steel
17-4 PH → High-strength precipitation-hardening stainless steel
Annealed 304 is generally considered non-magnetic or only weakly magnetic.
Cold working can partially transform the austenitic structure and increase magnetic response. Local magnetic attraction may therefore occur around formed areas, sheared edges, machined surfaces or cold-drawn material.
A magnetic response alone should not be used as proof that a component is not 304 stainless steel.
Annealed
High Ductility / Excellent Formability / Good General Corrosion Resistance
Cold Worked
Higher Strength / Higher Hardness / Reduced Ductility / Potentially Higher Magnetic Response
Solution Annealed
Restored Austenitic Structure / Improved Ductility
Conventional Hardening
Not Applicable
304 supports a wide range of mill, mechanical and chemical surface treatments. Finish selection should be based on appearance, cleanliness, corrosion exposure and functional surface requirements.
Passivation treatments are used after proper cleaning to remove free iron and surface contamination and support formation of a clean passive surface.
Compatibility: ✅ Excellent
Mechanical polishing reduces surface roughness and can improve appearance and cleanability.
Compatibility: ✅ Excellent
Brushing produces a controlled directional finish and is commonly used for visible sheet-metal surfaces, housings and architectural components.
Compatibility: ✅ Excellent
Electropolishing removes a controlled amount of surface material and can produce a smoother, cleaner surface with improved corrosion performance under appropriate processing conditions.
Compatibility: ✅ Excellent
Bead blasting can create a uniform matte appearance, but blast media and subsequent cleaning must be controlled to avoid iron contamination or inconsistent surface condition.
Compatibility: ✅ Good
Grinding is commonly used for weld cleanup, edge preparation and surface blending.
Dedicated stainless-steel abrasives and contamination control are recommended.
Compatibility: ✅ Excellent
304 can be laser marked for serial numbers, identifiers, logos and traceability information.
Compatibility: ✅ Excellent
Passivation ✅ / Mechanical Polishing ✅ / Brushing ✅ / Electropolishing ✅ / Bead Blasting ✅ / Grinding ✅ / Laser Marking ✅
Finish Selection Note:
For food, sanitary and corrosion-sensitive applications, consider surface roughness, contamination, weld cleanup and post-fabrication cleaning in addition to appearance.
Grade Selection
304 is commonly selected for equipment and components that need general corrosion resistance together with good forming and welding performance.
Typical Applications:
Tanks / Trays / Work Surfaces / Equipment Covers / Food-Contact Components
304 is widely used in food equipment, but chloride concentration, cleaning chemicals and operating temperature should be considered before specification.
Typical Applications:
Electrical Enclosures / Control Cabinets / Equipment Housings / Covers / Protective Panels
Its formability, weldability and surface-finish options make 304 well suited to fabricated sheet-metal assemblies.
Typical Applications:
Storage Tanks / Mixing Vessels / Containers / General Process Equipment
For aggressive chemicals or chloride-rich process media, confirm whether 316L or another higher-alloy grade is required.
Typical Applications:
Brackets / Support Frames / Equipment Bases / Machine Guards / Structural Panels / Fabricated Assemblies
Typical Applications:
Fittings / Flanges / Pipe Components / Valve Components / General Fluid-System Hardware
304 can be suitable for freshwater and many general services. More corrosive fluids require application-specific material review.
Typical Applications:
Bolts / Screws / Nuts / Washers / Pins / Mounting Hardware
Typical Applications:
Panels / Trim / Rail Components / Decorative Covers / Equipment Faceplates
Surface finish and environmental exposure should be considered together when the appearance of the component is important.
304 is a strong starting grade when the application requires general corrosion resistance and good fabrication performance without the additional alloying cost of more corrosion-resistant stainless steels.
Good resistance to ordinary atmospheric corrosion
Good performance in many freshwater and mild process environments
Excellent bending and forming capability
Excellent weldability
Good surface-finish options
Broad material availability
A widely specified general-purpose stainless steel
Moderate material cost within the stainless steel family
Main Requirement | Grade to Consider | Why |
Better Machinability | 303 | Developed for improved machining performance |
Higher Chloride Resistance | 316 / 316L | Molybdenum improves resistance to localized chloride corrosion |
Extensive Welding / Lower Carbon | 304L | Lower carbon reduces sensitization risk |
Higher Mechanical Strength | 17-4 PH | Precipitation hardening provides substantially higher strength |
Higher Hardness & Wear Resistance | 420 / 440C | Martensitic grades can be hardened by heat treatment |
Lower-Cost Ferritic Sheet Material | 430 | Nickel-free ferritic alternative for suitable environments |
Severe Chloride Service | 2205 / 2507 | Duplex grades provide higher chloride resistance and strength |
304 is often the reference point for stainless steel selection, but another grade may be more suitable when corrosion environment, machining productivity, welding requirements or mechanical properties dominate the design.
316 contains molybdenum and provides better resistance to chloride-induced pitting and crevice corrosion.
304 is typically selected for less aggressive general-purpose environments where the additional chloride resistance of 316 is not required.
CTA:
Compare 304 vs 316 Stainless Steel
304L is the lower-carbon version of 304.
The two grades have similar general corrosion behavior, but 304L is commonly preferred for extensive welding or applications where resistance to sensitization is important.
CTA:
Compare 304 vs 304L Stainless Steel
304 is an austenitic stainless steel with better overall corrosion resistance, ductility and weldability.
430 is a ferritic stainless steel that may provide a lower-cost option for selected sheet-metal and decorative applications in less demanding environments.
CTA:
Compare 304 vs 430 Stainless Steel
17-4 PH can achieve substantially higher strength through precipitation-hardening heat treatment.
304 is more suitable when formability, fabrication and general-purpose corrosion resistance are more important than high mechanical strength.
CTA:
Compare 304 vs 17-4 PH Stainless Steel
304 is available under several international designation and product-standard systems. The correct specification depends on material form, dimensions, required properties and project documentation.
Designation System | Designation |
AISI / ASTM Type | 304 |
UNS | S30400 |
EN Material Number | 1.4301 |
EN Designation | X5CrNi18-10 |
JIS | SUS 304 |
Equivalent designations are useful for identifying similar grades across standards, but they should not be treated as automatically interchangeable for every project.
ASTM A240 / A240M
Plate, sheet and strip for pressure vessels and general applications.
ASTM A276 / A276M
Stainless steel bars and shapes.
ASTM A312 / A312M
Seamless, welded and heavily cold-worked austenitic stainless steel pipe.
ASTM A269 / A269M
Seamless and welded austenitic stainless steel tubing for general service.
Other specifications may apply depending on product form and end use.
EN 10088-2
Technical delivery conditions for corrosion-resisting stainless steel sheet, plate and strip for general purposes.
EN 10088-3
Technical delivery conditions for corrosion-resisting stainless steel semi-finished products, bars, rods, wire, sections and bright products for general purposes.
Sheet / Plate / Coil / Round Bar / Flat Bar / Square Bar / Tube / Pipe / Rod / Wire
Availability depends on size, condition, surface finish, specification and supplier.
Annealed
Common for general fabrication, forming and corrosion-resistant applications.
Cold Worked
Used when increased strength, hardness or specific dimensional characteristics are required.
No. 1 / 2B / Bright Annealed / No. 4 Brushed / Ground / Polished
Finish terminology and requirements vary between ASTM and EN systems.
“304 stainless steel” alone is not a complete purchasing specification.
Where material control is important, drawings and purchase orders should identify:
Grade
Applicable material standard
Product form
Dimensions
Material condition
Surface finish where applicable
Required certification
Traceability requirements
304 FAQs
Material Support
Material selection should consider the operating environment, required mechanical properties, manufacturing process and applicable specification together.
NAITE TECH can review material requirements when a drawing or project specification requires confirmation before production.
Material selection can be reviewed against requirements such as:
Corrosion environment
Mechanical strength
Hardness
Operating temperature
Machining
Forming
Welding
Surface finish
Applicable material standards
Where 304 is not suitable, another stainless steel grade can be considered based on the application requirements.
For projects with controlled material requirements, the applicable specification can be reviewed together with:
Grade designation
Product form
Material condition
Required mechanical properties
Surface condition
Certification requirements
Traceability requirements
Material behavior during machining, forming, welding and finishing can affect both grade selection and manufacturing planning.
The purpose of this review is to confirm that the selected stainless steel grade is consistent with the drawing and operating requirements before production.
Specified grade, product form and material standard can be checked against drawing and purchase requirements.
Mill Test Reports, Certificates of Conformity and other supplier documentation can be provided when required and available for the selected material.
Heat, lot or batch information can be maintained where project traceability requirements apply.
Incoming stainless steel can be checked for identification, dimensions, surface condition and visible defects before manufacturing.
Material and quality records can be supplied according to agreed project requirements.
Quality Note:
Certification and traceability availability depend on the material specification, supplier and order requirements. Required certificates or traceability levels should be stated during the quotation stage.
Technical data and material-selection guidance should be checked against the specification applicable to the actual product form and project.
Primary reference sources for this page include:
ASTM International — stainless steel product specifications
EN 10088 — stainless steel grades and technical delivery conditions
British Stainless Steel Association — grade, fabrication and corrosion technical guidance
World Stainless — stainless steel material and corrosion references
Outokumpu — 304 / 1.4301 technical product data
Material standards take precedence over general website reference data when defining purchasing or design requirements.
If you are evaluating 304 stainless steel for your application, share your drawing, operating environment, material standard and performance requirements. Our engineering team can help review whether 304 is suitable or recommend an alternative stainless steel grade.
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